As the lung is considered to be one of the more effective, noninvasive route of administration to the systemic circulation, a number of powdered medications can be used to treat a variety of conditions that accompany a lot of different diseases. Conditions requiring an inhaler, particularly in such therapy where can be administered to a patient on a program of home care, include: (1) infection, (2) mucous edema, (3) tenacious secretions, (4) foam build-up, (5) bronchosplasms, and (6) loss of compliance.
Many useful medicaments, and especially penicillin and related antibiotics, are subject to substantial or, in some instances, complete alteration by the stomach juices when administered orally. Different patients will react differently to the same dosage at different times. On this account, in past oral dosages was supplemented by checking blood samples to ascertain how much medicament has found its way into the blood stream, or by parental administration.
Powdered medicaments administered by inhalation are not frequently used for delivery into the systemic circulation, because of various factors that contribute to erratic or difficult-to-achieve blood levels. Whether or not the powder drugs reaches and is retained in pulmonary alveoli depends critically upon particle size. The literature reports that the optimum particle size for penetration into the pulmonary cavity is of the order of ½ to 7 um.
The general properties given rise to errors of such inhalers in dispensing proper Medicaments are specific directional and velocity characteristics including instability and concentration of the mass of particles administered in a unit volume of air.
Moreover in a definitive clinical setting the patient's inhaling flow can vary significantly. During my research and development I have considered appropriate to test several types of Inhalers with different flow rate in order to develop a novel Inhaling Device, which is obviating the above described disadvantage, by effectively and smoothly inhaling one dose of powdered medicaments at a time into the pulmonary tract by the simple inspiration of air by a patient.
Several devices have been developed for the administration of micronized powders of relatively potent drugs, even if, at present, devices capable of dispersing dry powders contained in a capsule are not known at all. The Norisodrine Sulfate Aerohaler Cartridge (Abbott) is an example of such product. In the use of this Aereohaler, inhalation by the patient causes a small ball to strike a cartridge containing the drug. The force of the ball shakes the proper amount of the powder free, permitting its inhalation. Another device, the Spinhaler (Fisons), TurboHaler from Astra are propeller-driven device designed to deposit a mixture of lactose and micronized cromolyn sodium into the lung, other devices developed by Glaxo, such as Rotahaler, Beclodisk, Diskhaler, Ventodisk and Diskus, all for the administration of powdered drugs for the Respiratory Tract (like Ventolin, Albuterol, Salbritanol, Serevent, etc.) and several other types of these inhalators at present on the market, however most are cumbersome, complicated and expensive.
Consequently, these multi-dose devices have to be reused, whereas for reasons of hygiene and, particularly owing to the difficulty of keeping the mouthpiece clean, it would be proper and more convenient to have available an inhalator which can be disposed after one single use. Additionally present devices often result in problems of obtaining a proper mixture with the air during the transmission of the medication to the breathing portions of the body thereby affecting efficiency of the medicinal mixture.
But even if it's preferable to use this devices just once, the invention that is object of this patent has been realized in two embodiments: the first one is a disposable inhaler, while the second one can be used more times.
Clinical practice patients, who are often elderly people, find it difficult to understand the multi-disk method of loading and administering the dry powdered medicament. The illustrative page enclosed with the medicine, though clear, is nevertheless only theoretical. In synthesis everything is seen as complex and difficult and is thus refused. There is the actual possibility that the medicine is not administered because the patient has not noticed that the loader is empty after several doses. Then there are hygienic needs to clean the mechanism with the special brush, etc.
All this frequently results in the premature abandoning of the medicinal formulation, possibly to return to the spray. This, despite its apparent simplicity of use and rapidity, is liable to constant errors, both on the part of the patient and on the part of the nurses, so the spray is almost always delivered on the tongue and not in the lower respiratory tract, leading to repeated doses, with possible cumulative side effects. The serious matter is that the dry powder preparations are almost unknown even in the hospital environment, where the priority in potency and dignity of the “pill” medicine still exists, as it does outside the hospital.